The Genetics and Theology of Race

By Sy Garte

In much of the world, people struggle to make sense of issues related to race in public and personal life. Race has been an important political topic in the United States as well, and it has been a subject of controversy within American Christianity ever since the first slaves were brought to these shores. Christians led the abolitionist movement, but many slave owners also pointed to the Bible to justify the institution of slavery. The Civil Rights Movement began in the Black Church, and today churches continue to be concerned with racial questions within their own congregations as well as with racial divisions among humans created in the same image of God.

Discussions about the meaning and relevance of race often focus on social issues of justice, prejudice, and human relationships. At the same time, thanks to modern science, we can now easily discover details of our own racial and ethnic genetic heritage. Sometimes the results of these genetic ancestry tests are surprising and enlightening (1), but what do they really mean? What can science tell us about race that might help inform our understanding of social issues? The answer might surprise many people: not much.

Biology of Race

The truth is that race is not a biological parameter, and there is no scientific definition or objective test of human race (2-4). Race can only be defined culturally, not genetically. In fact, the only accepted method in biomedical science to determine a person’s race is to ask them how they self-identify (5,6).

At first this seems to be counterintuitive. Isn’t it true that white couples have white children and African-American couples have African-American children? So how could race not be genetic? To understand why race is not a genetic or biological construct among human beings, we need to delve just a bit into population genetics as applied to our species.

All humans have the same genes, but many genes come in different forms. The differences are small changes in the exact DNA sequence, and they often have no effect on how the gene acts to code for proteins. When they do have an effect, these differences can produce variation in the phenotype (often a person’s physical characteristics, which may include skin and eye color, body shape, hair, etc). Different forms of the same gene are called alleles. Each of us has two alleles for every gene, one from each parent.

Human Genetic Diversity

Having different alleles results in genetic diversity. For example, the genes that make an enzyme to metabolize alcohol have different alleles that cause differences in alcohol tolerance between individuals. Different populations have different frequencies of each allele, but there are no alleles that are diagnostic for race (which would require that all members of a race have a specific allele which is absent from other races). Some alleles are geographically selected for, such as those for lighter-colored skin in regions with low sunlight, and darker skin in sunny regions. Short stature is favored in hot and humid rainforests, so the alleles that are related to shorter height will predominate in populations living in such regions. Other environmental selection factors include climate, temperature, humidity, altitude, diet, and disease organisms. Together, these factors explain why there are some genetic differences between populations that come from different geographical regions (4,7,8).

But the genes that are subject to such environmental selection pressure represent a small minority (4,9). For most human genes, there are few or no major differences in allele frequencies between different populations. In fact, there is usually as much or more diversity within a population than between populations (6,8). There can be as many genetic differences between two Nigerians as between a Nigerian and a German.

How Many Races Are There?

Not only is it impossible to scientifically identify race, we can’t even use genetics to demarcate how many races exist. In the U.S., we often think in terms of three demographic races: European, African, and Asian. But this has no basis in the small genetic differences that do exist between these populations. If we were to assume that there are three races, then, based on differences in allele frequencies between geographical populations, they would have to be 1) Africans, 2) Europeans and Asians, and 3) Australians and Papuans. If we assume there are five genetically defined races, we will get 1) Africans, 2) Australians, Pacific Islanders, and some South Asians, 4) East Asians and Amerinds, and 5) Europeans and some West and South Asians. We could keep splitting up the human population into an arbitrary number of “races” based on small genetic differences – it has been done for up to 43 different racial groups (8). There is no bright line in these genetic differences between populations that tells us what the actual number of human races might be, so it is completely arbitrary to assign racial groups to populations.

One study that attempted to divide the human population into genetically defined groups identified four overall genetic clusters that came as close as possible to approximating populations we call Africans, Europeans, Asians, and Pacific Islanders (10). The so-called European cluster had 96% of two European populations, but also included 62% of the Ethiopians, 21% of the Afro-Caribbeans, and 9% of the Chinese. Every cluster had some people from each ethnic group, and no ethnic group fit into one single cluster.​ Even skin color correlates poorly with other population-specific genetic markers. Studies in Brazil and the U.S. show that while there are some weak correlations between skin color and geographic ancestry (Europe or Africa), there is so much overlap that it isn’t possible to know from an individual’s skin color how much African or European genetic ancestry they have (11,12).

So What Is Race?

Does all of this mean there is no such a thing as race? Of course not. Race is real, but it is a cultural construct, not a scientific one (13). We know this is true because the definition and characterization of “race” differs widely in different parts of the world.

The American concept of race is one of the most bizarre – it is unique in the world, and it is derived not from skin color, but from the economics of slavery (14).

Because of generations of white slave owners sexually exploiting their African slaves, many slave offspring were very fair-skinned. These slaves could have easily passed for white, which would have led to freedom and an economic loss for the owner. The slave owners’ answer was the “one drop rule”: any degree of known African ancestry made a person “black” even if they were lighter-skinned than many whites. While this rule was instituted in the South during slavery, it spread and became the ingrained American construct of race. Barack Obama was considered by most everyone to be the country’s first black president, not the first biracial president. New York Congressman Adam Clayton Powell, who represented Harlem, was lighter in color than many Italians and Greeks, but nobody ever considered him anything other than African-American.

While only Americans use this definition of race, the pattern of admixture is similar throughout the world. There are very few (if any) examples of genetic isolation of any human population. There has been so much migration, conquest, and outbreeding throughout human history that there are no “pure” races anywhere. Contrary to historically popular claims, Icelanders are as genetically heterogenous as other Europeans, and the Japanese are as “impure” as Koreans, Chinese, etc. Ethiopians are a dark-skinned population living in Africa who have about 50% non-African genetic ancestry (15).

Race vs. Ancestry​While some genetic diseases cluster in certain populations, it’s important to note that these are not race-specific diseases. Sickle-cell anemia, for example, is not a genetic disease of Africans. It is a genetic disease common among people originating from regions where malaria is prevalent or was prevalent until recently, which includes West Africa, southern Italy, Greece, the Middle East, and parts of Asia (16).

So what about ancestry DNA testing? If race is not genetic, how come a person can send in a sample and find out she is one-third Scandinavian and two-thirds English with a trace of American Indian and African? The genetic markers used for ancestry determination are mostly not functional genes but the kind of non-coding DNA fragments that are used in paternity testing. These tests are informative for several generations back but cannot give information on deep ancestry, because after a few generations, genetic information is diluted from the genome, and contributions from ancestors living more than 10-15 generations or so ago might no longer be visible (17).

All humans share a deep genealogical ancestry from Africa, but this does not show up in ancestry tests. In addition, the results of these tests are probabilities, not certainties, because there is great variability among individuals within a population.

If we want to understand deeper ancestry, we need to abandon genetics and use genealogy, which uses different methods and approaches. We know that everyone has 2 parents, 4 grandparents, 8 great-grandparents, 16 great-great-grandparents, and so on… As we double the number of ancestors we have for every generation back, we quickly arrive at a number that’s more than the total number of people who have ever lived. How does this work? The answer is counterintuitive to the way we usually think about ancestry and descent, but quite simple: the hundreds or thousands of your ancestors that lived a couple of hundred years ago were also my ancestors, and many will appear in both of our family trees more than once. This is called pedigree collapse, and it means that for people from the same general geographic area we don’t need to go very far back in time to find at least one common ancestor.

All people with European ancestry (which includes most African Americans and Native Americans) share common ancestors from about 900 to 1200 years ago (18). All people alive today have common ancestors who lived between only 6 and 10 thousand years ago (19). It may or may not be a coincidence that this time frame roughly corresponds to the presumed period of the creation of Adam and Eve. It’s crucial to note, though, that based on data on population genetic diversity, Adam and Eve could not have been the only ancestors of humankind.

Theology and Science of Race

The scientific conclusion about human races is in strong concordance with Christian theology. Christians are called to welcome people of all nations and backgrounds into the faith and hold that salvation is available for everyone. All humans are seen equally as children of God – all are one in Christ.

"Here there is no Gentile or Jew, circumcised or uncircumcised, barbarian, Scythian, slave or free, but Christ is all, and is in all." (Colossians 3:11, NIV)

"Then Peter began to speak: 'I now realize how true it is that God does not show favoritism but accepts from every nation the one who fears him and does what is right.' (Acts 10:34-35, NIV)

Jesus Christ ministered to the Roman Centurion and the Samaritan woman, Phillip baptized the Ethiopian court official, and Paul preached the good news to the Gentiles.

As the catechism of the Roman Catholic Church states, “Created in the image of the one God and equally endowed with rational souls, all men have the same nature and the same origin” (Catechism of the Catholic Church, para. 1934). A similar statement that reflects the unity of humankind before God comes from the United Methodist Church: “The United Methodist Church acknowledges that all persons are of sacred worth. All persons without regard to race, color, national origin, status, or economic condition, shall be eligible… to become professing members in any local church in the connection.” (Article IV of the UMC Constitution)

Christianity has of course had a checkered history when it comes to the theological understanding of the equality of all humanity. There were times when some Christians suggested that not all people were fully human, or at least not all were at the same level of humanity. This was sometimes used to justify slavery or oppression of non-Europeans, including Africans, Native Americans, Asians, and Aboriginal Australians (see church historian Bill Leonard's essay in this edition of God & Nature magazine). Science hasn’t always done better: as recently as the early 20th century, a form of pseudo-scientific racism denied the shared biological heritage of all human beings (20).​We now know that such doubts are to be cast aside as scurrilous, and that science is solidly behind the original teachings of our Lord. While this might not cure the racial tensions our nation faces, it should at least equip all Christians with the tools and fortitude of scientifically derived truth to go along with our Christ-following determination to see justice and mercy prevail.

13. Smedley A., Smedley B.D. 2005. “Race as Biology Is Fiction, Racism as a Social Problem Is Real. Anthropological and Historical Perspectives on the Social Construction of Race.” American Psychologist 60:16 –26

14. Hickman C.B. 1997. “The Devil and the One Drop Rule: Racial Categories, African Americans, and the U.S. Census.”Michigan Law Review95:1161-1265.

18. Olson S. 2003. Mapping Human History: Genes, Race, and Our Common Origins. Mariner Books.19. Rohde D.L.T., Olson S., Chang J.T. 2004. “Modelling the recent common ancestry of all living humans.” Nature. 431, 562–566.20. Barkan E. 1992. The Retreat of Scientific Racism: Changing Concepts of Race in Britain and the United States Between the World Wars. Cambridge University Press.

Sy Garte earned his Ph.D. in biochemistry and BS in Chemistry from the City University of New York. He has been a Professor of Public Health and Environmental Health Sciences at New York University, Rutgers University, and the University of Pittsburgh.

In addition to over 200 scientific publications in genetics, molecular epidemiology, cancer research and other areas, Sy is the author of four books, and of articles in Perspectives in Science and Christian Faith(PSCF) and The BioLogos Forum.

Sy recently retired from a senior administrative position at the NIH, and is now President of the Natural Philosophy Institute, where he is working on a John Templeton Foundation grant to study the theory of gene regulatory networks. Dr. Garte is Vice President of the Washington DC Chapter of the ASA, and a member of the John Templeton Foundation Board of Advisors. His blog is www.thebookofworks.com.